DESCRIPTION: (Applicant's Abstract) Understanding the variables controlling cocaine seeking by humans is an important aspect of treatment. Although research with humans is important, the complexities of environmental control and data collection make laboratory animal studies necessary as well. We have developed a procedure that provides 3 potential measures of drug seeking in laboratory animals: 1) the length of time animals spend in the location they receive drug, 2) responding to acquire the drug, and 3) choice between drug and an alternative reinforcer. The goal of this continuation is to determine if these 3 measures provide information about drug seeking. We will examine changes in these measures in response to independent manipulations which alter drug seeking. Aim 1. Examine drug seeking for smoked heroin in non-opioid dependent animals. These data will be compared to data obtained in our ongoing study of drug seeking for smoked cocaine. Aim 2. Examine the effects of food restriction on drug seeking for smoked cocaine and smoked heroin. Aim 3. Examine the effects of extinction and non-contingent stimulus delivery on drug seeking for smoked cocaine and smoked heroin. Aim 4. Determine the effects of opioid physical dependence on drug seeking for smoked heroin. Aim 5. Determine the effects of buprenorphine on seeking for smoked cocaine, smoked heroin in non-dependent animals, and chocolate candy. By measuring location preference, choice behavior, and responding, we believe that information about motivational processes relevant to human drug seeking will be elucidated. Such information can best be interpreted by comparing across maintaining events that engender different amounts of behavior, and recording changes in that behavior in response to pharmacological and environmental manipulations. Current approaches to medication development for drug abuse would benefit from a better understanding of basic motivational processes in drug-seeking behavior, how drug dependence may modify these processes, and whether specific pharmacological interventions can be targeted towards these processes.